Semipermeable layer for multilayer film



Dec. 16, 1941-. K. SCHINZEL 6 SEMIPEBMEABLE LAYER Fdji MULTILA'YE'B' FILM Filgd Dec. a, 1938 BLUE SENSITIVE EMULSION SEMI-PERMEABLE LAYER memmm III, III IIIIIIIA2 t L I .SEMl- PERMEABLE LAYER ZERL-EB RED SENSITIVE EMULSION SUPPORT Fig.2.

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v FILTER LAYER GREEN SENSITIVE EMULSION SUPPORT N RED SENSITIVE COLLODION LAYER PERMEABLE LAYER v LZIIIIIIIIIIIIIIII GREEN SENSITIVE EMULSION BLUE SENSITIVE EMULSION Patented Dec. 16, 1941 SEMIPERMEABLE LAYER FOR MULTI- LAYER FILM Karl Schinzel, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation or New Jersey Application December 8, i938, Serial No. 244,655 a In Austria May 9, 1936 Claims.

This invention relates to color photography and particularly to means for controlling the diffusion of processing solutions by means of impermeable orsemi-permeable layers in the film.

This application ls a continuation-in-part of my copending application, Serial No. 139,759, filed April 29, 1937, now Patent No. 2,226,639, granted December 31, 1940.

In the treatment of multi-layer photographic film, that is, film in which several sensitive layers are coated on one or both sides of a common support it is sometimes desirable to effect a difierential treatment of the layers so that difierently colored images are formed in them In order that theprocessing baths used to form the images do not aifect more than the desired layer or layers of the film it is frequently necessary to limit the action of the baths to less than all of the layers of the film. This has been attendant with some difliculty since the processing solutions ordinarily used permeate all of the layers (except the support layer) with nearly equal ease and rapidity.

In processes involving the use of compounds which couple with the oxidization product of a primary aromatic amino developer, a further difficulty has been that the coupler compounds when incorporated in the photographic layer, tend to diffuse from the layer into an adjoining layer. All of these difliculties tend to produce impure and undesirable pictures.

In the accompanying drawing Fig. 1 is a sectional view of a film according to my invention having three sensitive layers-on one side of a I support and 'Fig.' 2 is a sectional view of a film according to my invention having two sensitive layers on one side of the support and a third sensitive layer on the opposite side.

I have found in many processes of multi-color development that these difiiculties may be overcome by the meable layers at various locations in the film, for example, in a film having three differently sensitized layers coated on one side of a single support the middle layer may be separated from the top and bottom layers by layers which are only partially permeable or which are impermeable to the original developer. Where a sensitive layer is coated on the reverse side of the support, this layer may be overcoated with a partiallypermeable or impermeable layer which prevents action of the developer on this layer during development of the layers on the face of the support. The specific manner in which films may be treated in this way will now be described.

use of semi-permeable or imper-.

such as an alcohol-soluble For natural color photography a triple layer film can beused, coated on one side of a support l0 with layers II I! and I3 sensitive respectively to the red, green and blue regions of the spectrum. Semi-permeable layers [4 are coated. between the layer 1! and the layers II and I3. This is shown in Fig. l of the accompanying drawing.

A sensitive to my invention by coating a support ID, as shown in Fig. 2, on one side with green-sensitive layer l2 and blue-sensitive layer l3 and on the opposite side with red-sensitive collodion layer I5. The bluesensitive layer 13 and the green-sensitive layer l2 are separated by a yellow filter layer l6 and the red-sensitive layer I5 is overcoated with a layer I! which lacquer, benzyl-ether cellulose, a stearine layer soluble in the alkaline color development, etc., in order to be able to accomplish the development of one side of the film at a time. After completion of the part color image or images on the face of the film, the temporary coating is removed from the back and the color development of this side completed. Since the side carrying the two emulsion layers has the yellow filter layer It between them, the residual silver halide of the blue-sensitive emulsion can be made developable with blue light after-general black development and developed to the yellow part image. Both other emulsions can then be made developable with fogging agents, such as thiourea and one after the other developed independently to the desired color. The development of each of the layers may be carried out by means of a coupling development in whichacoupling component is present in the layers or in the developer as described in my application, Serial No. 139,759.

The diffusion of the processing solutions-into the film may be controlled in various ways. One

or both of the lower layers of the multi-layer film may be tanned or hardened to prevent dif- .fusion of the processing'solutions or hardened intermediate layers which may also serve as filter layers maybe used. Collodion intermediate or backing layers may be used and where both silver chloride and silver bromide emulsion layers are used as in my prior Patent No. 2,226,639, the differential'developing power of these layers may be taken advantage of in combination with the use of hardened or unhardened gelatin layers or collodion layers.

Furthermore, if one takes care of approximate difiusion of the reaction solutions in the layers film may also be made according at first retards development.

by proper composition of the solutions, many procedures may be made to allow more desirable results, than without this precaution.

Where the coupling components are to be incorporated in the sensitive layers before exposure, the coupler compounds frequently diffuse out of the layer in which they are incorporated. In this case it is possible to use semipermeable intermediate layers which permit the passage of developers and fixing solutions but do not allow the passage of the coupler molecules. This prevents the diffusion of the couplers from the sensitive layers but allows processing of the film containing the couplers in thelayers to the processing baths.

Also in three-color development'it is possible to tan the lower red-sensitive layer so strongly that it is not developed even in the original black and white development nor' in the color development of the other emulsion layers. After formation of color images in the upper emulsion layers, the last part image is developed with a strongly alkaline color developer or the redsensitive layer is de-tanned or the retarding action of the filter layer between the middle and bottom emulsion layers is removed by suitable agents. Instead of a tanned lower emulsion one can use a silver bromide collodion emulsion with general or color sensitivity increased by sensitization. 'After color development of the upper emulsion layer the collodion is made permeable by alcohol and developed to a colored image. Analogously, a lower weakly tanned silver halide emulsion could be protected by a colloidal in-' termediate layer which is dried before coating of the two upper emulsions and whose pores are opened by alcohol for color development of the lower silver halide emulsion only after completion of the two upper part color images.

The individual emulsion layers can also be separated by intermediate layers impermeable to the developer, especially the upper emulsion from the other ,two. These layers may consist of gelatin, collodion, cellulose acetate or any othersuitable colloid in order to enable the independent, direct or reversal color development. After completion of the upper part color image the tanning of the gelatin is removed or the collodion made permeable to aqueous solutions by alcohol,- acetone,'etc. followed by the development of the colored part images in the two lower layers according to .desired development methods. 7

In certain processe the intermediate gelatin layer are relied upon in part to-prevent diflusion. The superficial effect on the upper layer created by this can be attained more nearly perfectly if the middle layer is first treated so that it is excluded from the development and then forms, together with the two intermediate filter layers, a neutral zone of approximately triple thickness. After this inactivation of the middle silver halide layer, individual color development of the upper layer can then be accomplished by controlled diffusion of so many kinds that in the following only the most important ones can be explained:

In reversal development, the primarily reduced silver 01' all three silver bromide layers can be removed or at least converted into silver ferroc-yanide with potassium ferricyanide. Then the residual silver bromide of the middle layer potassium ferricyanide. The residual silver bromide of the two other layers is now'made developable with thiourea, stannous salt, etc., or by re-exposure, and the upper part image is obtained by superficial action of a color developer by known methods'of controlled diffusion, then in the usual manner the lower part image.

Similar results can be obtained with a triple layer having a silver bromide gelatin emulsion only in the middle; above and below, however, silver chloride emulsions, preferably with pure or colored or ultra-violet absorbing intermediate gelatin layers. Other colloids less permeable to water than gelatin can be used for the latter and also for the middle silver bromide layer. The middle silver bromide layer is especially desirable in two ways, as the following examples show:

The three layers are first submitted to a nontanning developer yielding a black image in each, and this is bleached out in the usual way. Then, after selective exposure of the middle layer to light to which it is differentially sensitive, and development of this layer to an appropriate color, a color developer acting specifically on silver chloride is allowed to penetrate superficially, of course, deep enough to develop completely the latent color image of the upper layer. An effect on the lower silver chloride emulsion is eliminated with certainty, since the surface developer to reach the lowest layer has to penetrate two gelatin intermediate layers, in addition to the middle silver bromide emulsion layer. The lower part color image is then developed by prolonged action of another color developer specific for silver chloride.

Another method is to allow a properly compounded solution of potassium ferro-cyanide to diffuse differentially and superficially after general ordinary development. This converts only the silver chloride of the upper layer into silver I ferrocyanide, but certainly does not act on the can be exposed to yellow or red light and deresidual silver chloride of the lower emulsion which latter is then directly developed in color. After reconversion of the silver ferrocyanide of the upper layer into silver chloride, this is re-' duced with a specific color developer, then the residual silver bromide of the middle layer after making it developable by thiourea, etc. It is less desirable to develop the residual silver bromide of the middle layer first in color after corresponding pre-treatment and only to then reduce the silver ferrocyanide ,of the upper layer after conversion into silver chloride or directly with a vigorous color developer. The silver ferrocyanide of the upper layer could be converted into the corresponding part color image either directly or after colored development of one of the two other part images, also by conversion into a colored ferrocyanide etc. or into a mordanting body according to processes of toning.

What I claim is:

1. A multi-layer' hotographic film comprising a transparent support having on one side thereof three superposed gelatino-silver halide layers each sensitive to a difierent region of the spectrum and containing coupler compounds capable of forming colored photographic images on development of the film in a primary aromatic amino developing agent, said film having between the middle emulsion layer and each of the other emulsion layers, semi-permeable layers which permit the passage of photographic developing and fixing solutions but which retard the passage of the coupler compounds incorporated in the A sensitive layers. 4

2. A multi-layer photographic film comprisin a transparent support having on one side thereof tween the middle emulsion layer and each of the other emulsion layers, semi-permeable cellulosic layers which permit the passage of photo'- graphic developing and fixing solutions but which retard the passage of the coupler compounds incorporated in the sensitive layers.

3. A multi-layer photographic film comprising a transparent support having on one side thereof three superposed gelatino-silver halide layers each sensitive to a different region'of the spectrum and containing coupler compounds capable of forming colored photographic images on development of the film in a primary aromatic amino developing agent, said film having between the middle emulsion layer and each of the other emulsion layers, semi-permeable collodion layers which permit the passage of photographic developing and fixing solutions but which retard the passage of the coupler compounds incorporated in the sensitive layers.

4. A multi-layer photographic film comprising a transparent support having on one side thereof three superposed gelatino-silver halide layers each sensitive to a different region of the spectrum and containing coupler compounds capable of forming colored photographic images on development of the film in a primary aromatic amino developing agent, said film having between the middle emulsion layer and each of the other emulsion layers, semi-permeable cellulose'acetate layers which permit the passage of photographic developing and fixing solutions but which retard the passage of the-coupler compounds incorporated in the sensitive layers.

5. A multi-layer photographic film comprising a transparent support having on one side thereof three superposed gelatino-silver halide layers each sensitive to a diilerent region of the spectrum and containing coupler compoundscapable of forming colored photographic images on development of the film in a primaryflaromatic amino developing agent, said film having between the middle emulsion layer and each of the other emulsion layers, semi-permeable gelatin layers which permit the passage of photographic developing and fixing solutions but which retard the passage of the coupler compounds incorporated in the sensitive layers.

, KARL SCHINZEL. 

